Factors Associated With Upstaging of Melanoma Thickness on Final Excision

The incidence and risk factors associated with upstaging from initial biopsy to definitive excision in cutaneous melanoma have not been established. The aim of this study was to determine the incidence of tumor stage upstaging and associated risk factors using the National Cancer Database.

A retrospective study of the National Cancer Database between 2012 and 2016 was performed. The cohort of patients undergoing excision of melanoma with available data comprised 133,592 patients. Differences in characteristics for upstaging were determined using Wilcox rank-sum, chi-square, or Fisher's exact tests. Multivariable analysis was performed using logistic regression to determine factors associated with upstaging.

Incidence of upstaging was 5.2%. Upstaged patients were older, male, of non-White race, and of lower education level (P < 0.001). Lesions of the head/neck and lower extremity had increased incidence of upstaging compared to the trunk (P < 0.001). Nodular and acral lentiginous melanoma was associated with higher incidence of upstaging compared to superficial spreading melanoma (P < 0.001). Patients with lymphovascular invasion had increased risk of upstaging (P < 0.001).

Upstaging of melanoma is infrequent but is significantly more prevalent in non-White patients and those with lower educational status. Provider and patient education should include the higher risk of upstaging in these groups and the possible need for further surgical intervention, such as re-excision of margins and sentinel lymph node biopsy.